influent.internal.util.Futures Maven / Gradle / Ivy
/*
* Copyright 2016 okumin
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package influent.internal.util;
import java.util.concurrent.CompletableFuture;
/**
* Utilities for {@code CompletableFuture}.
*
* This is expected to be used in only Influent project.
*/
public final class Futures {
private Futures() {
throw new AssertionError();
}
/**
* Creates a new {@code CompletableFuture} that will be completed
* when the given original future is completed.
* But the original future will not completed even when the new one is completed.
*
* {@code CompletableFuture}'s completion is a mutable state
* and can be changed by anyone after the future is passed.
* The owner of a future can pass that safely if using this function.
*
* @param original the original future
* @param the type of {@code CompletableFuture}'s value
* @return the future that depends on the original future
* but the original future does not depend on
*/
public static CompletableFuture followerOf(final CompletableFuture original) {
return original.thenApply(java.util.function.Function.identity());
}
}